Area-wise, 39% bigger.
Running new supply line under parking area
- Thread starter John-Charleston
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John-Charleston
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I guess I could run copper once I have the PVC in place. It was 3/4 copper originally and there were no issues so I think that will be sufficient. This building is 70+ ft long with one unit in the front and one in the rear. The supply splits right inside the front crawlspace wall and from there the supply to the rear unit was 3/4 PB that I changed out to 3/4 PEX. I've not gotten any complaints but I haven't checked the water pressure in the rear unit myself. Can I assume that PB has a similar id to PEX?
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No, but you can assume you should not use PB (polybutylene ) pipe, especially with city water. You are not going to use lead pipe either.
Why would you not be thinking of putting 1 inch PEX through 1-1/4 PVC? In some areas, copper would need to be type L and would probably be soft copper. Wasn't the former copper soft copper? Anyway, I suspect that will not be attractive to you when you price it.
Polyethylene pipe (other than PEX) could be very attractive, but it needs to be transitioned to something else outside of the living space. Silly rule IMO, but rule it is.
Jeff H Young
In the Trades
No one has recommended 3/4 but might be good enough .
Jeff, I don't think he can afford the 1" line, that's why he's trying to get the plumbers here to okay his idea. This guy is on a really tight budget.
A standard one-bath home with kitchen sink, dishwasher, water heater, clothes-washer, 1.6 tank toilet, lavatory, tub/shower combo and two hose bibs would be counted as 18 fixture units.
Most standard two bath homes consisting of kitchen sink, dishwasher, water heater, clothes-washer, two 1.6 tank toilet, two lavatories, one shower, one tub/shower combo, and two hose bibs would be counted as 23.5 fixture units.
Most standard three bath homes consisting of kitchen sink, dishwasher, water heater, clothes-washer, three 1.6 tank toilet, four lavatories, two showers, one tub/shower combo, one whirlpool bath and two hose bibs would be counted as 34 fixture units.
If this is a duplex, you're looking at 36 fixture units. That's a 1" water service all day long.
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Why would you not be thinking of putting 1 inch PEX through 1-1/4 PVC? In some areas, copper would need to be type L and would probably be soft copper. Wasn't the former copper soft copper? Anyway, I suspect that will not be attractive to you when you price it.
If you use regular copper pipe, how do you intend to splice the pieces? Solder couplers? I think some places allow that, and some don't. Soft copper usually does not need a sleeve. I am not sure about regular copper-- I suspect it does not either.
Polyethylene pipe (other than PEX) could be very attractive, but it needs to be transitioned to something else outside of the living space. Silly rule IMO, but rule it is.
John-Charleston
Member
Well I have never mentioned using PB or lead so I'm not sure where that's coming from. I didn't think of using 1" Pex because I had no idea that might be needed. The original incoming line was 3/4 copper and was working fine. Until I learned differently on this forum, I didn't know that 3/4 Pex had a smaller id than 3/4 copper. Now it's something I'll look into.
John-Charleston
Member
Sorry but you're supposing something I've never said or suggested. I'm not "trying to get the plumbers here to okay his idea" but just asking questions. Budget is not the problem (though I don't like spending money that's unnecessary) I just started with a 3/4" line and mistakenly assumed all 3/4" lines would have the same water flow. It's been working fine with 3/4 copper since the mid-70's afaict. Now that I learn that 3/4 Pex might not allow the same flow, I may need to re-think it.
I came here to ask about water jetting a line under the parking area. In the process I've learned that my plan for 3/4" Pex might not be a good idea. That's what forums like this are for. In truth, I've inadvertently tested the 3/4 Pex idea because that's what I temporarily hooked up the line with when I had to leave town. (I have 40' of 3/4 Pex trailing across the ground to the crawlspace) Tomorrow I'll have time to go there and re-assess what I'm faced with.
Jeff H Young
In the Trades
Don’t want to force the point but 3/4 is substandard work it might be ok but a lot of us don’t want to advocate that be done. just a little on the small side and not recommended .
John-Charleston
Member
At least in copper it's been working fine.
Jeff, I responded before I saw your last post. Yes, I get that 3/4 is considered undersized. I'll figure out more tomorrow, thanks.
You did mention PB, but I guess you didn't say you were considered using it. Was that because that material had been in place there at some time in the past? I leapt to conclusion that you were considering it, and I attempted some satire by bringing up lead.
John-Charleston
Member
That's right, I mentioned PB but only to say that I removed the PB that was already in place when I bought the duplex. To my knowledge it's not even possible to buy PB plumbing these days (at least in the US).
John-Charleston
Member
Gotcha. So Pex has a smaller id than even PB. .715 for PB and .680 for Pex.
So ideally, I would upsize the Pex to 1" and take it to where it splits for the two units in the crawlspace and at that point use a 1 x 3/4 x 3/4 fitting to split the incoming line to the two supply lines (one to each unit). I guess that would also mean that I'd want to start with a fresh connection to the meter and eliminate the short run of original 3/4 copper that's coming off the meter now.
Pressure drops add, rather than being limited by the size of the smallest element.
Its like 1000 ohms in series with 33o ohms has less resistance that 1000 ohms in series with 1000 ohms.
My point being that if you have a short length of copper that you can easily adapt to the 1 inch pex, that might be better to keep in line if connecting to the meter would potentially involve some connection that was hard to deal with. I don't know how complex it is to connect to a meter. For all I know, connecting the pex to the meter with the right adapter would be easy enough. Watch for thermal effects, and don't pull the pex tight.
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See https://www.huduser.gov/portal/publications/pex_design_guide.pdf including page "77" and "78" (real 87,88).
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